Fire extinguisher



Dec. 11, 1951 Filed Oct. 15, 1946 G. E. FERGUSON ET AL 2,578,528

FIRE EXTINGUISHER 2 SHEETS-SHEET INVENTORS. GEORGE ,E.FERGUs0N FREDERICKADODELIN ATTOENE G. E. FERGUSON ETAL 2,578,528

Dec. 11, 1951 FIRE 'EXTINGUISHER 2 SHEETSSPEET 2 Filed Oct. 15, 1946 S1 9 m 7. 13 2 mm u 5 7 nu 4 TUD I 3% 3 24 M mmm 5 8 U .3 E 2 2 N R r ER G F 9 .r 1 Y B 0 a u A TTOEZV after use.

Patented Dec. 11, 1951 UNITED STATES PATENT OFFICE FIRE EXTINGUISHER George E. Ferguson, Spring Valley, N. Y., and

Frederick A. Dodelin, Glen Ridge, N. J., assignors to Pyrene Manufacturing Company, Newark, N. 3., a corporation of Delaware Application October 15, 1946, Serial No. 703,354 (c1. 169--33) Claims.

This invention relates to fire extinguishers and more particularly to small extinguishers of the hand operated pump type provided with a reciprocating piston for discharging the fire extinguishing contents of the device.

While fire extinguishers of the character indicated, as heretofore constructed, have given an excellent record of performance when the extinguishers are properly maintained, improper maintenance results in an inoperative extinguisher. On such occasions when an emergency arises, which requires the use of the fire extinguisher, it is impossible to operate it due to the serious corrosion of the working parts. In most cases this inoperative condition is due to the employment of an improper charge of fire extinguishing fluid in refilling the extinguisher A fluid other than that intended for use with the device is sometimes introduced. For example, devices of this type are ordinarily intended for use with chemically dry, neutral halogenated hydrocarbons, such as carbon tetrachloride base liquids. It is important in the use of such liquids that they be free from water.

' Sometimes the refill, due to improper manufacture or improper care in storage, will contain a certain amount of water or moisture and this, in the course of time, will bring about corrosion difiiculties. The water within the fire extinguisher, either in liquid or vapor form, tends to hydrolyze the fire extinguishing fluid and, in the case of carbon tetrachloride, serves to produce and release hydrochloric acid. This acid will attack brass or bronze and other metals of which the fire extinguishers are ordinarily constructed and will bring about corrosion, which will result either in the rupturing of certain parts of the device, when an attempt is made to use it, or in the sticking of parts, which will prevent use of the device.

Even in instances in which the original, propor charge of fire extinguishing fiuid is still present in the device, corrosion difficulties have occurred and these have been particularly diificult to overcome. In the manufacture of fire extinguishers of the character mentioned, each extinguisher, is normally subjected to test to determine its tightness against leakage. Many extinguishers which pass this test prove to be satisfactory over long periods of time, while others, which appear to be equally satisfactory in the course of the test, become corroded in some way over a period of time. This occurs even though they may contain the, original charge which was free of water at the time it was introduced. Accordingly, an extinguisher which may never have been used over a long period of time, but which is suddenly required {or use, may prove to be substantially inoperative with the result that all fire extinguishers of this general character are then condemned by those who encounter these experiences.

Apparently the corrosion diificulties in the situation just mentioned arise from the fact that in the course of time certain extinguishers undergo a sort of breathing action due to repeated changes in atmospheric conditions, such as temperature, barometric pressure, and humidity. There are a number of points in a fire extinguisher where parts which must have,relative movement, serve to provide communication between the interior and exterior of the device, unless proper seals are provided. It has been found difficult, moreover, to determine whether a seal will remain effective over a long period of time. For example, a cork seal is sometimes effective for a long time but some cork seals are subject to attack by the vapors given off by carbon tetrachloride and deteriorate in a comparatively short time. Two sections of cork cut from the same piece are found to react diiierently to such vapors. Attempts have been made to overcome this difficulty by enclosing a cork gasket or washer in lead foil, or by otherwise covering the cork with lead. However, even gaskets of this sort have been found to lose their effectiveness over a period of time due to the attack on the cork within the lead covering by the hydrochloric acid gas developed within the extinguisher. In the course of time the breathing action, which is permitted by the failure of one or more of the seals of the extinguishers, will result in the introduction of a substantial amount of moisture into the charge and the same corrosive action will result as in the case of water initially present in the charge. Once the hydrochloric acid gas is developed, this attacks the lead foil around the cork seal, thus destroying the seal and permitting further moisture to enter the extinguisher from the atmosphere.

It has been a primary object of the present invention to eliminate, so far as possible, all corrosion inducing factors of fire extinguishers as heretofore constructed and to thus provide a structure which will be ready for use at all times regardless of the length of time which has elapsed since the extinguisher was last inspected and found to be in good working order. Various expedients have been tried or recommended heretofore for the foregoing purpose, but, for one reason or another, these prior attempts to overcome the corrosion difiiculty have not proved successful. In some instances they have been partially eifective and have increased the useful life of an extinguisher, but in the long run, some extinguishers have been found to fail in time of need.

In accordance with the present invention the life of a fire extinguisher may be increased almost indefinitely in so far as deterioration from the corrosive action of the charge is concerned. It has been found necessary in achieving this end to employ a combination of features, all of which interact and contribute toward the attainment of the common end. None of the features per se, when employed independently of the others, serve to achieve the desired result, although certain of the features, when used separately or as a part of the entire combination, will produce results greatly superior to any heretofore attained.

Two features employed in combination have been found important to the full success of the invention. These are: (1) the provision within the extinguisher of a solid substance which is constantly effective to remove water from both the liquid and the vapor content of the chamber and which is, at the same time, effective to neutralize any free acid, and (2) the provision of thoroughly effective sealing means resistant to the action of the liquid and vapor content of the extinguisher as well as to the moisture or other constituents of the outside atmosphere, these sealing means being provided at all points where relative movement takes place between parts accessible to both the interior and the exterior of the extinguisher. A further specific feature of the inventio'n'is the formation of the various sealing means above mentioned of a material which is not merely resistant to the vapors released from the charge but which has an advantageous slight tendency to swell and thus become even more effective as a seal after reaction with the vapors than before.

Other objects, features, and advantages of the invention will appear from a detailed description of an illustrative embodiment of the same. which will now be given in conjunction with the accompanying drawings, in which:

Figure 1 is a longitudinal axial section through a fire extinguisher embodying the present invention;

Figure 2 is a transverse sectional view taken along the line 2-2 of Figure 1;

Figure 3 is a transverse section through a part of the pump system andis taken along the line 3-3 of Figure 1;

Figure 4 is a detail view of a portion of the top closure member for the extinguisher;

Figure 5 is a longitudinal axial section through a modified form of extinguisher embodying the invention;

Figure 6 is a transverse sectional view through the modified extinguisher, taken along the line 6-6 of Figure 5; and

Figure 7 is an enlarged detail view in axial section through the upper portion of an extinguisher of either of the types illustrated in Figures 1 and 5.

Turning now to the drawings, and particularly Figures 1 to 4 and '7, the fire extinguisher illustrated is in general of a type heretofore produced. It comprises an outer body 10, formed of brass or the like, having a cap or closure member H at one end provided with a flange I2 adapted to fit over the end of the body. The construction is rendered airtight at this point by any suitable means as by brazing or soldering the cap and main body of the shell together. At the lower end of the shell there is provided a discharge nozzle or nipple l3 which is incorporated in any suitable way in the bottom wall of the body so as to form an airtight juncture. Fitted into the nozzle [3 and forming a close fit therewith is a discharge tube M of relatively small diameter, this tube being secured by solder or the like and extending upwardly along the axis of the body to a point above the cover member It, as indicated at l5. Surrounding the tube i l and spaced slightly therefrom, to provide an annular channel around the tube I4 is a piston tube which carries adjacent its lower end a piston 11. Below the piston I! the tube i5 is provided with a cap [8 having screw-threaded engagement with the lower end of the tube. In the operation of the piston tube, in the manner to be explained, the cap [8 slides along the tube and forms a reasonably effective seal in relation thereto. The first part of the upward movement of tube i5 is idle, until the cap !8 strikes the underside of the piston, and then the piston and tube travel together.

Toward its upper end the piston tube is provided with a small internal annular shoulder 19 beyond which the wall thickness of the tube is slightly reduced. A handle member 2% fits relatively tightly over the upper end of the tube l5 and is secured to the latter in any suitable way. As shown, this connection may comprise a screwthreaded member 2| having threaded engagement with the upper end of the tube and having an annular recess adapted to receive a tapered pin 22 which may be driven into a suitable opening extending through the flat upper portion of the handle.

A spring 23 is mounted within the top portion of the tube l6 and bears at its upper end against a sealing member 2 which is thus forced against the bottom of the member 2|. Sealing member 24 is preferably provided with a small downwardly extending flange formed by a frustoconical depression in the bottom of the sealing member. This arrangement is such that the pressure imparted to the member 2 by the spring 23 has a component acting outwardly upon the flanged portion of the member and thus squeezes this against the inner wall of the tube it to provide an exceptionally tight seal.

Member 24 may be formed of any suitable material which is not subject to attack or deterioration by moisture or other constituents of the normal atmosphere, or by the fire extinguishing fluid or vapors therefrom, or gases developed within the fire extinguisher as a result of hydrolysis, corrosion, and the like. It must have suitable compressibility, elasticity, and softness, or plasticity, to enable it to conform readily to the slight irregularity of the metal surface which it engages and at the same time to return to substantially its initial condition upon release of compression. These properties, moreover, must be retained over a wide range of temperatures, i. e., from +60 C. to i5 C., and over a long period of time. An exceptionally desirable material for the purpose has been found to be a modified form of vinyl resin which comprises a vinyl resin base and suitable filler, plasticizing and stabilizing substances. A particularly desirable sealing member may be formed of a polyvinyl acetate-chloride complex, comprising about 5% polyvinyl acetate and 95% polyvinyl chloride with tricresyl phosphate as a plasticizer and having a molecular weight of between 12,000 and 20,000, to which has been added suitable amounts of the other substances mentioned. As a filler there may be added, for example, equal amounts of carbon black and wood flour, these combined being present to the extent of about 6% of the mixture. Any appropriate substances may be added as plasticizers and stabilizers, the character of these being such that they will not react with the carbon tetrachloride or other polychlorinated hydrocarbon forming the fire extinguishing charge. The stabilizer may also assist in rendering the vinyl resin resistant to reaction with the charge. The mixture may be formed of 60 to 70% polyvinyl resin, 30 to 37% plasticizer, l to 3% carbon black, and 2 to 5% wood flour or other cellulose filler. A specific composition of the above character which is suitable for the purpose is that available under the trade name and designation Tygon S28-1. The plasticizer employed in this is tricresyl phosphate and the fillers'employed are carbon black and Wood fiour or similar cellulose filler.

At its opposite end the spring 23 acts against a thimble or cartridge or cup-like member 26 slidable within the tube [6. When the handle is retracted the spring 23 serves to slide the cup 26 within the tube until the lower lip of the cup strikes the shoulder I9. However, when the handle is locked in its depressed position, shown in Figure '7, the spring 23 is compressed somewhat and the cup 26 is held spaced a short distance from the shoulder l9. Cup 26 has a base 21 against which the spring 23 acts and within its interior the cup carries a small disc or cylinder 28 of a suitable sealing material, preferably of the same type as the member 24. When the handle is locked, this sealing disc is forced by the action of the spring- 23 against the free upper end of the discharge tube I4, which passes through the lower open end of the cup, thus efiecting a tight seal at this point against the introduction of air through the nozzle [3 and tube 14 into the interior of the extinguisher.

The lower end of the handle is expanded somewhat to form a socket having at its extreme lower end a pair of laterally extending projections 29 adapted to provide a bayonet connection between the handle and a lock plate or retainer 30 secured to the upper end of the body of the extinguisher. The lock plate has a pair of inwardly extending arcuate flanges 3'! adapted to cooperate with the projections 29, the arrangement being such that as the handle is pressed inwardly and the projections are passed between the ends of the flanges and the handle is then rotated, the projections 29 and flanges 3| will have a slight camming action tending to draw the handle inwardly against the lock plate and will 'then look the parts in this position. A bushing 32 is provided with flanges which cooperate with the lock plate 30 and the edge of an opening in the top ll of the body to clamp these parts together in airtight relation. The bushing also provides a bearing for the reciprocatory movements of the piston tube l6.

Within the lower sleeve-like extension of the handle 20 there is mounted, for axial movement therein, a member 33 having a sleeve portion fitting snugly between the inner surface of the handle and the outer surface of the tube I6 and having a cupped lower end providing a laterally extending portion 34 adapted to cooperate with a shoulder 35 on the handle. Within the cupped lower end of the member 33 there is held a washer or gasket 36 preferably formed of the same type of material as the sealing element 24. This washer is arranged to be squeezed between the inner surface of the radially extending part 34 of member 33 and the upper end 31 of the bushing 32. The. gasket and the bushing preferably have the configuration indicated in Figure 7, i. e., the end of the bushing has a frusto-conical depression. As will be seen, the gasket is then not only squeezed firmly against the end of the bushing but is also forced inwardly by the frustoconical surface against the outer surface of the tube 16. This effects a tight seal around the tube. Squeezing of the gasket 36 is initially broughtabout by a spring 38 acting between a shoulder within the handle 20 and the upper end of the member 33. As the handle is driven home and locked by the plate 30 the camming action of the projections 29 and flanges 3| serves to impart an extra squeeze to the gasket. When the handle is released the spring 38 serves to urge the member 33 outwardly or downwardly and as the handle is re-engaged the sleeve is forced back into the handle and compresses the spring 38 until shoulders 34 and 35 are brought into solid engagement. At the lower end of sleeve 32 a further sealing means 39 is preferably provided around the tube Hi. This may be of any suitable form, such as packing material or a washer or gasket of any appropriate material. A ring 40 surrounding the tube I6 at the inner end of the sleeve 32 serves to retain the sealing means in the pocket or stuffing box provided for it at the inner end of the sleeve.

Within the body It there is also provided a pump cylinder 4| in which the piston I1 slides and which has at each end a valve fittin 42. These fittings may be of identical construction, but as shown are provided in inverted relationship. A reduced portion 43 of the upper fitting serves to provide a bearing for the tube [6. A stripper member may be provided adjacent this reduced neck portion of the upper fitting and may serve to retain a suitable packing material 44 as shown in Figure 7. The corresponding valve fitting at the lower end of the extinguisher may suitably have merely a bushing 46 fitted within the neck 43 and adapted to provide a relatively tight bearing fit with the discharge tube I4. The outer end of the bushing 46 may be flanged as indicated at 4-1 to form a thrust bearing in relation to the inner face of the nozzle l3.

Each of the fittings 42 has a lateral extension 48 into which is fitted an auxiliary tube 49 of substantially smaller diameter than the tube 4|. The tube 49 serves to connect the two valve fittings to provide a double acting pump capable of operating regardless of the angle at which the extinguisher is held. An inlet 50 is provided in the extension 48 and this opens into a small chamber 5| in axial alinement with the tube 49. A ball valve 52, however, is adapted to close the passage between the chamber 5| and a chamber 53 with which the tube 49 directly communicates. When the parts are held in the position indicated in Figure 1, the ball 52 closes the passage between the chambers 5! and 53 in the upper valve fitting, but it does not close this passage in the lower fitting. It is, in fact, held from so doing by the weight of a rod 54 which is loosely mounted within the tube 49.

As best shown in Figure 3, communication is providedbetween thechamber 53 anda chamber 55 formed within the main part of the fitting 42 in line with the cylinder M. This com-- munication is by way of an opening 5 in the wall of the fitting which provides free access between the chamber 55 and an intermediate valve chamber 51. The latter in turn is in communication with the chamber 53 through a passage 58 adapted to be closed by a ball check valve 59.

The foregoing arrangement is such that with the extinguisher held in the position shown in Figure l, as the handle is drawn upwardly the piston I? will move upwardly within the cylinder ii after a short idle movement of the tube It. This will cause liquid from within the body iii to be drawn in through the opening 5 of the lower fitting 42, thence into the chamber b3 of this lower fitting, into chamber 5! and finally into chamber 55 and cylinder 5|. The ball valve 52 and 55 of the lower fitting will'be inactive at this time so as to permit the indicated flow of the liquid. Assuming that liquid had previously been introduced into the upper end of the cylinder 4| upon a previous reciprocation of the piston, this liquid will be squeezed between the piston and the upper end of the cylinder and hence will be forced through an opening 5b in the wall of the tube l6 into the interior of the latter. In this connection it should be noted that on the initial upward movement of the tube it with the handle 20 the relative movement which will have taken place between the tube it and the piston l'l, until the cap Ill engages the underside of the piston, will have served to expose the opening 60 above the piston for the passage of the liquid in the manner explained while a similar but lower opening 5! will have been closed-off. The liquid in the upper end of the cylinder 4| and the chamber 55 cannot be discharged through the passage 56 into the chamber 53 because of the action of the bail check valve 59.

As the handle is now forced inwardly in the opposite direction, the tube l6 will first slide in relation to the piston I! to assume the relative positions shown in Figure i. This serves to expose the lower opening 6! and permits discharge of the liquid from the lower chamber 55 and the lower end of cylinder 3! 6| into the interior of tube [6. Opening 59 will, at this time, be closed-off by the piston. Check valve 59 in the lower fitting prevents discharge of this liquid into the lower chamber 53 and back into the body. Liquid Will, however, be drawn into the upper side of the cylinder it through opening 56 of lower fitting t2 thence upwardly through tube 4% into the upper fitting 52 and from the latter into upper chamher 55.

The liquid thus forced into the tube it on either direction of movement of the piston ii passes upwardly to the top of the discharge tube l4 and then downwardly through the discharge tube since at this time the sealing member 1 will have been retracted from. the end 55 of this tube by the outward movement of the handle. Thus a stream of the fire extinguishin liquid will be discharged through the nozzle 13 upon both directions of movement of the handle. It should be noted in connection with the foregoing that the check valve 52 prevents the introduction of air into the tube 49 to break the suction on the liquid in the bottom of the shell. Should the extinguisher be tilted to direct the nozzle through opening I3 upwardly against the ceiling, for example, the operation of the two fittings 42 will be reversed. The rod 54 will shift by gravity and thus permit the check valve 52 in the lower fitting to assume a closing position with respect to the chamber 53, while the check valve 52 in the upper fitting will be held open at this time. Thus the proper suction will take place -.upon the liquid which will have shifted by gravity flow to the end or the body which is closed by the cap I l. Futhermore, the two valve fittings 42 and the associated parts are permitted to turn relatively freely, in the course of operation of the pump, about the tubes It and i6 upon which they have their bearings. The balance of weight is such, furthermore, that the inlets 55 of the valve fittings will be held in the l wermost portion of the shell, when the ex tinguisher is disposed in a horizontal position, regardless of how the body may be held or rotated in the hand of the user. This enables the discharge of substantially all of the liquid from within the body without regard to the position in which the body or the handle may be held.

An important expedient is the provision within the sealed chamber of the extinguisher of a solid material capable of removing any water or moisture which may find its way into the extinguisher. This material is preferably also adapted to neutralize any acid which is either introduced in the charge or formed within the extinguisher upon storage. It is important that the material employed for this purpose should not react with the effective ingredients of the fire extinguishing charge but merely with contaminants in the charge. It is also important that the purifying material employed, and also any reaction products resulting from a reaction between the purifying agent and the moisture or other impurities in the charge, shall not have a deleterious effect upon the fire extinguishing fluid. For example, it must not substantially modify the dielectric properties of the fiuid, otherwise the extinguisher would be of little benefit in the case or" fires started by electric short circuits and the like. It is also important that the purifying agent does not produce a sediment within the extinguisher which may become lodged in one or another of the ball check valve passages or any of the other passages within the pump system. Furthermore, it is important that the purifying agent be capable of removing moisture and other impurities both from the liquid charge and from the vapors in the space above the cha'rge and of combining with or otherwise retaining the moisture other impurities in such manner as to prevent their further chemical reaction with the extinguishing fluid or the vapors therefrom.

With the foregoing peculiar and special requirements of the problem, in view, it has been found that highly. satisfactory results may be obtained through the use of small pellets or granules formed of a mixture of anhydrous calcium sulfate and calcium oxide. If desired, a mixture of separate granules or pellets of the two substances may be used. The calcium sulfate serves to absorb the water or moisture content of both the charge and the vapor within the extinguisher and produces from it a set plaster of Paris or hydrated gypsum. It should be noted in this connection that any water which may accumulate within the extinguisher will normally float on the surface of the charge. The lime present in the pellets will react-with any acid produced within the extinguisher and will thus maintain a neutral condition. In lieu of calcium sulfate there may be used anhydrous cupric sulfate, calcium chloride, or other substances capable of combining with the water in the system and thus removing it from possible reaction with the charge. In lieu of the lime, which forms calcium hydroxide in the presence of water, there may be used any of a number of other alkaline substances, such as calcium carbonate or magnesium oxide or carbonate; so also, a mixture of any of these substances ma be used. The amount of lime or other alkaline substance or mixture present in the purifying agent maybe quite small. It need not be more than about 2 5% of the entire mixture, although a somewhat greater amount may be provided if desired. Cal-- cium chloride as commercially available normally contains a sufficient amount of lime and other alkaline substances to be suitable for the formation of the pellets or granules of the present invention, without the addition of other alkaline substances.

' In order to retain the purifying agent in such a way that it will not interfere with the operation of the pump system and at the same time will be accessible for purifying both the liquid and vapor space within the body, a foraminous basket 62 has been provided, this basket being mounted upon the upper valve fitting 42. The top of the basket may simply be provided with an opening large enough to fit over the neck 43 of the valve fitting. The bottom of the baskethowever, must have a larger opening adapted to fit over the two chambers 55 and 51 of the valve unit. So, also, the cylindrical wall of the basket must be cut away in the region of the chamber 5i to permit the basket to be passed over and around the inlet opening 50 of the valve unit. While the basket is preferably formed of a perforated metal sheet, formed of brass or the like, and is preferably tincoated, it may be formed of other materials and in other ways. It may, for example, be a wire basket formed of tin-coated copper wire, or of stainless steel or the like.

In the normal use of the extinguisher the liquid charge, which is introduced through the opening provided in the cap H upon the removal of a plug 63 (Figure 4), will fill the extinguisher to a level about half the depth of the basket 62. Plug 63 is sealed by a washer 63a, formed of any suitable material such as the vinyl resin composition hereinabove mentioned. It will be understood that the extinguisher, when not in use, is normally supported by a bracket or the like in the position indicated in Figure 1, so that a part of the basket will be immersed in the liquid charge and a part will be exposed to the vapors in the space above the liquid. As will be seen, the construction and arrangement of the basket 62 is such that it will not interfere in any Way with the operation of the extinguisher. It will permit the free movement of the pump parts, including the gravitational adjustment of the parts in accordance with any movements of the body of the extinguisher about its axis when held horizontally. Furthermore, the purifying agent and also the reaction products will, at all times; remain in the basket 62 and will not interfere with the operation of the system. A single charge of the purifying agent, provided in the basket 62, will last indefinitely in the normal use of the fire extinguisher. However, in the event that an extinguisher is subjected to abnormally hard usage, the contents of the basket 62 may be emptied and replenished upon the removal of the top closure II of the body of the extinguisher.

The location of the basket is such that whenever a fresh charge of extinguishing fluid is introduced into the body through the opening closed by the plug 63, the charge will pass through the basket and will thus be subjected to a filter:- ing or purifying action.

Referring now to Figures 5 and 6, there is shown a modified arrangement for retaining the purifying agent. In general, the extinguisher of this modified construction may be the same as that of Figures 1 to 3. However, the purifying agent, in lieu of being contained in a foraminous basket, is simply in the form of a stick 64 which is retained by aspring member 65 having a plurality of resilient clamping fingers 66 secured thereto, by which the spring retainer maybe mounted upon the cylinder 4| of the pump-mechanism. Spring 65 and fingers B6 are preferably formed of stainless steel. This arrangement is again such that a part of the stick will'normally be immersed in the fire extinguishing liquid, while another part will project into the vapor space above the liquid. The stick 64 may be formed of the same substance or mixture of substances as the granules, pellets, or lumps used in the basket of Figure 1 To lend support to the material as it reacts with the water or acid within the extinguisher it may be compressed around a suitable core, such as a stainlesssteel wire;

If desired, both the foraminous basket and the stick might be employed in order to insure the presence of a part of the purifying agent within the liquid and a part within the vapor space, regardless of the position in which the fire extinguisher is kept when not in use. Thus, if the extinguisher were kept in a horizontal position while not in use, the stick 64 might be largely, if not entirely, in the vapor space of the extingui'sher, but a portion of the foraminous basket would, in that case, be immersed in the liquid.

While certain illustrative embodiments of the invention have been disclosed in considerable detail, it will be understood that numerous changes may be made in the construction, arrangement, and operation of the various parts without departing from the general principles'and scope of the invention. Other forms of purifying agent having the characteristics above specified may be employed. so also other materials having the required properties may be utilized in the formation of the various sealing elements hereinabove described. Moreover, while the invention relates particularly to fire extinguishers using carbon tetrachloride, it is applicable also to those charged with other halogenated hydrocarbons, such as bromine o fluorine substitution products- For example, dib'ro'm methane or methyl bromide or mo'nofior methane may be used.

What we claim is: g

1. In a fire extinguisher comprising a closed body having a discharge orifice at one endand an opening at the other end in axial alinement with said orifice, a discharge, tube extending from said orifice to and through said opening to-a point exterior of said body, a pump having a cylinder within said body surrounding said discharge tube, a piston tube passing through said opening and; extending into said. cylinder around said discharge tube, said piston tube carrying a piston within said cylinder and having an operating handle exterior of said body, and a lock plate on said body for normally holding said handle inactive, the combination of a plurality of disc-like sealing members carried by said handle and formed at least in part of a polyvinyl ll acetate-chloride resin containing a plasticizer and fillers which are inert to the fire extinguishing liquid, said plasticizer being tricresyl phosphate and being present to the extent of about half the weight of the copolymer said sealing members being arranged to render said body vaportight when said handle is held by said lock plate, one of said members being perforated to fit snugly about said piston tube.

2. In a fire extinguisher of the pump type adapted to retain and discharge a halogenated hydrocarbon fire extinguishing liquid having a body for retaining said liquid, a liquid discharge member having an orifice for the passage of said liquid, a reciprocating pump for discharging the liquid through said member, means exterior of said body for operating said pump, and means for locking said operating means in one position in relation to said body, the improvement which comprises a disc-like sealing member formed principally of a polyvinyl acetate-chloride resin containing a plasticizer in the form of tricresyl phosphate to the extent of about half the weight of the copolymer and fillers which are inert to said extinguishing liquid mounted in said pump operating means and arranged to be held against said discharge member at said orifice to seal the same when said operating means is locked in said position.

3. In a fire extinguisher of the pump type adapted to retain and discharge a halogenated hydrocarbon fire extinguishing liquid having a body for retaining said liquid, a liquid discharge member having an orifice for the passage of said liquid, a reciprocating pump for discharging the liquid through said member, means having a portion exterior of said body and having a portion extending through an aperture in said body for operating said pump, and means for locking said operating means in one position in relation to said body, the combination of a perforated sealing member formed principally of polyvinyl acetate-chloride resin containing a plasticizer in the form of tricresyl phosphate to the extent of about half the weight of the copolymer and fillers which are inert to said fire extinguishing liquid, said resin formulation being of such character that the sealing member is caused to swell slightly and eifect a more perfect seal on reaction with the vapors released from the fire extinguishing liquid, said sealing member being arranged to surround said second mentioned portion of said operating means and to cooperate with said aperture in said body, and a disc-like sealing member formed of substantially the same resin mixture as said first mentioned sealing member and so carried by said pump operating means as to be held against said discharged member at said orifice to seal the same when said operating means is locked in said position.

4. In a fire extinguisher of the pump type adapted to retain and discharge a halogenated hydrocarbon fire extinguishing liquid having a body for retaining said liquid, a liquid discharge member having an orifice for the passage of said liquid, a reciprocating pump for discharging the liquid through said member, said pump comprising a piston within said body, a reciprocable piston tube carrying said piston and extending through an aperture in said body and a handle secured to said tube exterior of said body, and means for locking said handle to said body when the piston tube is in its innermost position, the combination of a plurality of sealing members formed principally of a polyvinyl acetate-chloride resin containing a plasticizer in the form of tricresyl phosphate to the extent of about half the weight of the copolymer and fillers which are inert to said fire extinguishing liquid, said resin formation being of such character that the sealing members are caused to swell slightly and effect a more perfect seal on reaction with the vapors released from the fire extinguishing liquid, said sealing members being disposed within said handle and adapted to seal said discharge member at said orifice, said aperture and the connection between the piston tube and handle when said operating means is locked, said sealing members being disc-like and one being perforated to surround said piston tube.

5. In a fire extinguisher of the pump type adapted to retain and discharge a halogenated hydrocarbon fire extinguishing liquid having a body for retaining said liquid and providing a vapor space above the liquid, a liquid discharge member having an orifice for the passage of said liquid, a reciprocating pump for discharging the liquid through said member, said pump comprising a piston within said body, a reciprocable member carrying said piston and extending through a wall of said body to the exterior thereof, and a handle secured to said member exteriorly of the body, said body, discharge member and reciprocable member providing passages for the movement of gases between the interior and the exterior of said body, the combination of sealing means formed at least in part of a polyvinyl acetate-chloride resin containing a plasticizer in the form of tricresyl phosphate to the extent of about half the weight of the copolymer and fillers which are inert to said fire extinguishing liquid cooperating with all of said passages to seal the same when said member is in its innermost position, and means for retaining within the body of said extinguisher a dehydrating agent in solid form which is inert to said extinguishing liquid mounted within said body partly within the liquid and partly within the vapor space thereof.

GEORGE FERGUSON. FREDERICK A. DODELIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,097,145 Snelling May 19, 1914 1,231,815 Verdone July 3, 1917 2,116,319 Miller May 3, 1938 2,148,770 Mittendorf Feb. 28, 1939 2,204,798 Ferguson June 18, 1940 2,326,861 Huthsing Aug. 17, 1942 OTHER REFERENCES Vinylite resins booklet, copyright 1942, by Carbide and Carbon Chemicals Corp, 30 East 42nd Street, New York, N. Y. 

